Coaxial jack plug



May 9 1961 s.PAs1K coAxIAL JACK PLUG Filed Deo. 11, 195

mvENToR.

AGENT Q "illll -Illlll- .lllll i illlllllllill yar/Zz S J United StatesPatent t COAXIAL JACK PLUG Saul Pasik, Syosset, N.Y., assigner to ReevesInstrument Corporation, Roosevelt Field, N.Y., a corporation of New YorkFiled Dec. 11, 1957, Ser. No. 702,026

9 Claims.- (Cl. 339-183) This invention relates to coaxial connectors,and in particular to an improved coaxial jack plug of the type used inthe plugboards of electronic computing machines.

It is a principal object of this invention to provide an improved andrelatively inexpensive coaxial jack plug which permits maximumutilization of plugboard space.

Another object is to provide a coaxial jack plug which grounds theconductive shield of the coaxial cable through a grounding plate formingpart of the plugboard.

Still another object is to provide a coaxial jack plug which isself-latching when fully inserted in a plugboard aperture.

Yet another object is to provide a coaxial jack plug which may be easilyinserted and withdrawn from the plugboard without grounding the innerconductor of the coaxial cable to the plugboard grounding plate.

`A further object of the invention is to provide an improved coaxialplugof reduced size for use with small diameter coaxial cable.

Shielded coaxial cables having jack plugs at each end are often used inmaking interconnections on the circuit connecting panels, or plugboards,of electronic apparatus. The outer conductor, or metallic shield, of thecoaxial cable is grounded by connecting it through a iirst conductiveelement of the jack plug to a grounding plate forming part of theplugboard while the inner conductor is coupled through a secondconductive element of the jack plug to a mating contactor.

The coaxial jack plug of this invention comprises an elongated hollowsleeve which is conductively attached at its rearward end to themetallic shield of the coaxial cable. The forward end of the sleeveconsists of a plurality of longitudinal resilient lingers having lateralprojections extending outwardly beyond the outer surface of the body ofthe sleeve. The inner conductor of the coaxial cable is conductivelyattached to a stud which is centered within the hollow sleeve. Tubularinsulators separate the stud from the sleeve thereby electricallyinsulating one conductive element from the other. The outer diameter ofthe portion of the insulator located adjacent to the resilient lingersof the sleeve is made slightly less than the inner diameter of thesleeve in order to permit the lingers to be deilected inwardly when thejack plug is inserted or removed from the plugboard. The forward end ofthe stud is provided with a conductive member which is protected by aninsulating ltip to prevent shorting of the member to the plugboardgrounding plate.

The above objects of and the brief introduction to the present inventionwill be more fully understood and turther objects and advantages willbecome apparent from a study of the following detailed description inconnection with the drawings, wherein,

Fig. 1 is a longitudinal sectional view of the jack plug inserted in aplugboard aperture,

Fig. 2 is a view similar to Fig. l which shows the jack plug beinginserted or removed from thev plugboard,

W 4ice Fig. 3 is an exploded view showing the components.

which comprise the jack plug,

Fig. 4 is a perspective view of the jack plug sleeve,

and

Fig. 5 is an end View of the sleeve.

The jack plug of the present invention is most usefu l when used inconnection with electronic computing ma-4 chines of the type providedwith either fixed or removable plugboards containing rows and columns ofapertures.

by effecting electrical contact between jack plugs inserted in theapertures of the removable board and the op positely located contactors.f Y

Referring to Figs. l and 2 of the drawing, 10 represents a removablelaminated plugboard having rows and columns of circular holes of which11 is a single example.l

The plugboard 10 includes a panel 12 of insulating material and aconductive plate 13 bonded thereto. Plate 13 is grounded by an externalconnection not shown in the drawing.

As depicted in Figs. 1 and 3, portions of the insulating jacket 14 andprimary insulation 15 of coaxial cable 16 are removed thereby exposingthe ends of the inner conductor 17 and metallic shield 18. Shield 18 isfolded back over the jacket 14 of cable 16 and a ferrule 19, made of asoft, conductive metal such as brass, is secured around shield 18 and apart of primary insulation 15. Ferrule 19, as shown in Fig. 3, isinitially formed inthe shape of an inverted U having serrated edgeswhich overlap when the ferrule is crimped about coaxial cable 16.

An insulating washer 20 is placed over the inner conductor 17 andpositioned against the ends of primary insulation 15 and yferruleY 19.The inner conductorv 17 is then inserted in axial opening 2,1- inconductive stud 22, stud 22 having a receiving portion 23 of hexagonalcross section and a cylindrical forward threaded portion 24. Stud 22which may, for example, consist of silver plated brass is crimped at 25to secure it to inner conductor 17.

A lirst tubular insulator 26, having an inwardly extending flange 27 atone end is pressed over the hexagonal receiving portion 23 of stud 22with ilange 27 positioned against step 28 of stud 22. The tubularinsulator 26 is preferably formed of a tetrauoroethylene resin identiedby the trademark Teon This material is characterized by the propertythat it tends to return to its original shape if it is expanded and thenreleased. By making the inner diameter of insulator 26 slightly lessthan the diagonal distance across the corners of the hexagonal portionof stud 22, insulator 26- will tend to contract to its original diameterafter being forced over the stud thereby gripping the stud andpreventing relative rotation between the two parts.

An elongated hollow sleeve 29, which may be extruded from hardenedPhosphor bronze, is next slid over the components thus far assembledwith i-ts inside shoulder 30 butted against flange 27 of insulator 26and with its inside surface contacting the outer surfaces of ferrule 19,washer 20, and tubular insulator 26. The sleeve is afriixed to theassembly by crimping at 31, 32, and 3.3, the crimps at 311 and 32resulting not only in an excellent electrical connection between themetallic shield 18 and ferrule 19 but also in preventing" rotation ofthe elements of the coaxial cable relative to one another. Crimps 31 and32 also produce a connection of suflicient mechanical strength towithstand the tensile stresses normally imposed on the coaxial cable andjack plug. VA shallow crimp is used at 33 to avoid piercing insulator 26and possibly shorting s1eeve29 to stud 22.

As shown in detail in Figs. 4 and 5, four longitudinal slots 34 are cutin the forward end of hollow sleeve 29 thereby forming four resilientfingers 35. The forward end of each finger is provided with a latch 36which extends radially outward from 4the bodyof the' sleeve, the leadingand trailing edges, 36a and 36b of latch 36 being inclined with respectto the outer surface of finger 35. The outer diameter of the body of thesleeve is selected so that it may be slideably inserted in the plugboardaperture 11, and a shoulder 37, having an outer diameter greater thanthat of aperture 11, is provided to prevent insertion of the jack plugpast its fully engaged position.

A second tubular insulator 38, having a rearward flange 39 with an outerdiameter equal to the inner diameter of sleeve 29, is placed over thevforward portion 24 of stud 22. Forward flange 40 of tubularin'sul'ator3S extends beyond the forward edge of sleeve 29 and has a diametersubstantially equal to the outer diameter of the body of sleeve 29. Thecentral section 41 of tubular insulator 38 has an outer diameter lesslthan the inner diameter of reslient fingers permitting the fingers tobe deflected inwardly by a radial force on latch 36.

An internally threaded conductive contacting member 42, suitably ofsilver-plated brass, is screwed on to the threaded end of stud 22. Theposition, diameter and length of member 42 are selected to insure a goodelectrical connection with spring contactor 43 and at the same time makeit impossible to short member 42 to conductive plate 13 when the jackplug is normally inserted or withdrawn from the plugboard. Thus, theouter diameter of conductive member 42 is less than the outer diameterof the forward flange of tubular insulator 38 and its length withrespect to the thickness of the plugboard is short enough to preventaccidental contact with plate 13. An insulating tip 44 having a roundedforward end and a threaded axial opening at the other end is screwed onto the end of stud 22 to prevent shorting conductive member 42 to plate13.

An insulating sheath 45, preferably of rubber, is placed over therearward end of the jack plug assembly with its forward end positionedagainst shoulder 37 and its rearward end surrounding the insulatingjacket ofrcoaxial cables16. Sheath 45 electrically insulates sleeve 29while supporting cable 16 adjacent to the plug, thereby increasing itsresistance to bending fatigue. Sheath 45 also provides a convenient gripfor grasping the plug while inserting and withdrawing it from theplugboard.

When the jack plug is introduced into aperture 11 of plugboard 19, theleading edges 36a of latches 36 engage the edge of circular opening 11in panel 12. The force applied to each latch 36 has a radial componentwhich deflects resilient fingers 35 inwardly so that, as the plug isforced into the aperture, the latches lie within the circumference ofthe opening,V as shown in Fig. 2. Fingers 35, since they are maintainedunder tension, exert a radial outward force against the side of aperture11 thereby tending to hold the plug correctly centered in the opening.

The jack plug is inserted until shoulder 37 of sleeve 29 strikes againstthe outer surface of panel 12, as illustrated in Fig. l. In thisposition, the forward portions of latches 36 extend beyond conductiveplate 13 with the trailing edges 36b pressed against the forward edge ofaperture 11 by the spring action of partially deflected resilientfingers 35. The outward pressure exerted by fingers 35 on the edge ofthe opening securely hold the plug in position while at the same timeproviding an excellent electrical connection between sleeve 29 and plate13. A path for the ground current is provided through metallic shield18, ferrule 19, and sleeve 29, to grounding plate 1.3. The distancebetween the forward edge of shoulder 37 and a median point on trailingedge 36b of latch 36 is made equal to the thickness of plugboard 10.

With the jack plug fully inserted as shown Yin Fig. l, member 42 isconductively engaged with spring contactor 4 43. When a pulling force isapplied to the fully inserted plug the trailing edges 36b of latches 36engage the edge of opening 11 in plate 13 thereby applying a radialinward force which dellects fingers 35, until latches 36 lie within thecircumference of the opening permitting the plug to be withdrawn fromthe plugboard.

A significant feature of this invention is that a coaxial jack plug isprovided having a conductive sleeve which aids in accurately guiding andpositioning the plug when it is inserted or removed from the plugboard.The sleeve also retains the plug securely in position when it has beenfully inserted in the plugboard and simultaneously provides a groundingconnection for the coaxial cable shield. Furthermore, no springs orother holding devices are rcquired as part of the plugboard therebysimplifying both the design and manufacture of the board.

As many changes could be made inthe above construction and manydifferent embodiments of this invention could be made without departingfrom the scope thereof, it is intended that all matter contained in theabove description or shown in the accompanying drawing shall beinterpreted as illustrative and not in a limiting sense.

What is claimed is:

l. A coaxial plug comprising an elongated hollow sleeve adapted forconductive attachment at its rearward end to the outer conductor of acoaxial cable, saidsleeve including a forward end comprising a pluralityof longitudinal fingers having lateral projections at the ends thereofextending radially outward from the outer surface of said fingers, saidfingers being resiliently flexible to permit said lateral projections tobe depressed to an inner position substantially flush with the outersurface of saidV sleeve, a conductive stud coaxially positioned withinsaid hollow sleeve, said stud having its rearward end adapted forconductive attachment to the inner conductor of said coaxial cable andi-ts forward end extending outside the forward end of said sleeve,tubular insulating means having a first portion coaxially positionedbetween said hollow sleeve and said stud and having a flange portionsituated outside the forward edge of the fingers of said sleeve, theouter diameter of the first portion of said insulating means being lessthan the inner diameter of the longitudinal fingers of said sleeve topermit inward deflection of said longitudinal fingers, the diameter ofthe flange portion of said tubular insulating means being substantiallyequal to the outer diameter of said sleeve, and conductor means attachedto the forward end of said stud adjacent to said flange portion.

2. The coaxial plug as defined by claim l, wherein said conductor meanscomprises a tubular member coaxially disposed upon said stud to form anelectrical connector, the outer diameter of said tubular member beingless than the outer diameter of the flange portion of said insulatingmeans.

3. The coaxial plug as defined by claim 2, wherein the forward end ofsaid stud extends beyond the forward end of said tubular member, and aninsulating tip attached to the forward end of said stud.

4. The coaxial plug as defined by claim 3, wherein the outer diameter ofsaid insulating tip substantially equals the outer diameter of saidtubular member.

5. The coaxial plug as defined by claim 1, further includng aninsulating sheath surrounding the rearward end of said hollowconductivesleeve, said sheath extending beyond the rearward end of saidsleeve and being adapted to support said coaxial cable at a point spacedfrom the end of said sleeve. y

6. A coaxial plug comprising an elongated hollow sleeve adapted forconductive attachment at its rearward end to the outer conductor of acoaxial cable, said sleeve having a forward end comprising a pluralityof longitudinal resilient fingers, latching means affixed to the forwardend of the outer surface of said longitudinal ngers, a conductive studcoaxially positioned within said hollow t sleeve, said stud having arearward portion adapted for conductive attachment to the innerconductor of said coaxial cable and a forward portion extending beyondthe forward end of said sleeve, a first tubular insulator coaxiallypositioned between the rearward portion of said stud and said hollowsleeve, a second tubular insulator having its central section positionedbetween the forward portion of said stud and the longitudinal fingers ofsaid sleeve and having a flange portion situated outside the forward endof said sleeve, said central section having an outer diameter less thanthe inner diameter ofsaid sleeve to permit said resilient fingers to bedeflected to an inner position wherein the outer edge of said latchingmeans is flush with the outer surface of said sleeve, said flangeportion having an outer diameter substantially equal to the outerdiameter of said sleeve, and conductor means attached to the forward endof said stud adjacent to said flange portion.

7. A jack plug adapted for conductive attachment to a coaxial cable,said cable having an inner conductor and a metallic shield insulatedfrom and surrounding said inner conductor, comprising an elongatedhollow conductive sleeve having a forward end comprising a plurality oflongitudinal lingers with lateral projections extending outwardlytherefrom, said fingers being resiliently flexible to permit saidlateral projections .to be depressed to an inner position substantiallyflush with the outer surface of said conductive sleeve, conductive meansadapted to couple the rearward end of said hollow conductive sleeve tothe metallic shield of said coaxial cable, a conductive stud coaxiallypositioned within said hollow sleeve, said stud having an axiallylocated aperture in its rearward end adapted to receive the innerconductor of said coaxial cable and having its forward end extendingoutside the forward end of said sleeve, tubular insulating means havinga rst portion coaxially positioned between said hollow sleeve and saidstud and a flange portion situated outside the forward end of saidsleeve, the outer diameter of the first portion of said insulating meansbeing less than the inner diameter of the longitudinal fingers of saidsleeve to permit inward deliection of said longitudinal lingers, thediameter of the flange portion of said insulating means beingsubstantially equal to the outer diameter of said sleeve, and conductormeans attached to the forward end of said stud adjacent to said llangeportion.

8. A coaxial plug for use with a plugboard comprising in combination anelongated hollow conductive sleeve, said sleeve having a forward endconsisting of a plurality of longitudinal fingers each including alateral projection at the end thereof extending radially outward fromthe outer surface, said ingersbeing resiliently flexible to permit rsaidlateral projections to be depressed to an inner position substantiallyflush with the outer surface of said sleeve, a conductive studpositionedwithin said hollow conductive sleeve and having a threadedforward end extending outside the forward end of said sleeve, a rsttubular insulating means surrounding the rear end of said Stud andcompressed Within said sleeve for securing said stud in coaxialalignment within said sleeve, a second tubular insulating meanssurrounding the forward end of said stud, said second tubular insulatingmeans having a first portion situated between said stud and the lingersof said sleeve and having a flange portion situated outside the forwardedge of the fingers of said sleeve, the outer diameter of the firstportion of said second insulating means being less than the innerdiameter of said sleeve to permit inward deflection of said longitudinalngers, the diameter of the flange portion of said second tubularinsulating means being substantially equal to the outer diameter of saidsleeve, a threaded conductor engaging the threaded forward end portionof said stud and adjoining the flange portion of said second tubularinsulating means, the diameter of said conductor being less than theouter diameter of the flange portion of said second insulating means,and an insulated tip attached to the forward end of said stud adjacentto said conductor.

9. A coaxial plug comprising an elongated hollow sleeve adapted forconductive attachment at its rearward end to the outer conductor of acoaxial cable, said sleeve including a forward end carrying conductivelatching means having lateral projections extending radially outwardfrom the outer surface of said sleeve, said latching means beingresiliently llexible to permit said lateral projections to be depressedIto an inner position substantially ush with the outer surface of saidsleeve, a conductive stud coaxially positioned within said hollowsleeve, said stud having its rearward end adapted for conductiveattachment to the inner conductor of said coaxial cable and its forwardend extending outside the forward end of said sleeve, tubular insulatingmeans having a first portion coaxially positioned between said hollowsleeve and said stud and having a flange portion situated outside theforward end of said latching means, the outer diameter of the firstportion of said insulating means being less than the inner diameter ofsaid sleeve, the diameter of the flange portion of said tubularinsulating means being substantially equal to the outer diameter of saidsleeve, and conductor means attached to the forward end of said studadjacent to said flange portion.

References Cited in the file of this patent UNITED STATES PATENTS1,574,958 Denny et al. Mar. 2, 1926 2,449,073 Johannesen Sept. 14, 19482,695,394 Watts Nov. 23, 1954 2,832,941 Willis Apr. 29, 1958 FOREIGNPATENTS 770,170 France June 25, 1934

